The optical sensor touch panel and the relevant techniques thereto are revealed in the recent days. Such a touch panel has a matrix composed of light sources and detectors therein and the position of the input touch is detected via sensing the optical image. When an input touch is provided to the touch panel, the light from the light source would be obstructed and hence the detector corresponding thereto would not receive the signal. If the position which the detector does not receive the signal is determined, the position of the input touch would be identified accordingly.
Moreover, another kind of optical sensor touch panel is operated with an optical sensor pen, which includes a light transmitter and a light detector therein. The light transmitter of the optical sensor pen would transmit a light to the touch panel having a code pattern and the light detector would receive the light reflected therefrom. When the optical image is determined via the code pattern, the position of the input touch is able to be identified. Such a touch panel achieves the input detection in a short distance and has a great reflectivity which is beneficial to be integrated in a liquid crystal display (LCD) panel.
The optical sensor touch panel and the LCD panel are typically fabricated from the liquid crystal (LC). The cholesteric liquid crystal (CLC) substance has a similar spiral structure as the cholesteric molecules for the biomedical applications. The CLC substance has the optical activity, the ability for selectively optical-scattering and the dichroism for circular polarization, and moreover, the reflectivity for the lights having the similar optical activity is up to 50%. Therefore, the CLC substance is applied in several optical components for the LCD. The spontaneous alignment method for manufacturing the cholesteric reflective polarizer is disclosed in U.S. Pat. No. 6,721,030, wherein a lamination process is performed on the photopolymerized CLC substance, so that the photopolymerized CLC substance is oriented in a specific orientation for being a polarizer. Moreover, the coloring medium composed of the CLC microflake is disclosed in U.S. Pat. No. 6,753,044. The disclosed coloring medium has an improved brightness and color characteristics.
Based on the above discussions, for further taking advantage of the CLC substance, a method for manufacturing a coding plate for the optical touch panel is provided in the present invention. The coding plate is fabricated from the novel material, CLC substance, and is integrated into the LCD panel, so as to provide an input panel. The coding plate of the present invention has a great reflectivity, so that the optical performance of the input panel is maintained. Furthermore, the code pattern of the coding plate is also well protected thereby.